A power conversion device, which includes an insulation type full bridge converter and can switch a power transmission direction at a high speed, is provided. A DC/DC converter (10) constitutes a power conversion device, which operates as a first type converter that converts a voltage within a first range applied to a first input/output terminal pair into a voltage within a second range and outputs the voltage from a second input/output terminal pair or a second type converter that converts a voltage within the second range applied to the second input/output terminal pair into a voltage within the first range and outputs the voltage from the first input/output terminal pair, as a device in which a direction of a current flowing through a winding of a transformer (TR) is switched after a magnitude of the current flowing through the winding of the transformer (TR) reaches “0.”